The invention relates to an illuminating system having a fly-eye-integrator for a microlithographic projection exposure arrangement. The invention also relates to a microlithographic projection exposure arrangement including an illuminating system having a fly-eye-integrator and a method for producing microstructured components with a microlithographic projection exposure arrangement including an illuminating system having a fly-eye-integrator.
U.S. Pat. No. 4,682,885 discloses an illuminating system of the kind referred to above. The light of a mercury vapor lamp is received by an elliptical collector mirror and is directed onto an optical integrator which is configured as a special embodiment of a fly-eye-integrator. The optical integrator mixes light and generates a plurality of light beams which are superposed in an image plane by a condenser optic and there illuminate a rectangularly-shaped field. The optical integrator comprises two pairs of plates having cylinder lenses. The cylinder axes of the cylinder lenses of a pair are parallel and the cylinder axes of the pairs are directed perpendicularly to each other. The two plates of a pair are mounted in the mutually opposite focal plane of the cylinder lenses. A rectangularly-shaped field having a lateral aspect ratio of greater than 1:1 is illuminated in the image plane via focal lengths of the two pairs with the focal lengths being of different sizes.
U.S. Pat. No. 5,926,257 discloses an illuminating system having a fly-eye-integrator which has a configuration similar to the fly-eye-integrator disclosed in U.S. Pat. No. 4,682,885. The cylindrical lenses are configured as diffractive elements having a cylindrical effect.
U.S. Pat. No. 5,963,305 likewise discloses a fly-eye-integrator comprising two pairs of plates with cylindrical lenses wherein the pairs of plates are arranged perpendicularly to each other. Refractive and diffractive embodiments of the cylinder lenses are shown.
The fly-eye-integrators disclosed in U.S. Pat. Nos. 4,682,885; 5,926,257 and 5,963,305 have the disadvantage that the diaphragm plane of the illuminating system downstream of the fly-eye-integrator is only incompletely illuminated when the beam, which impinges on the fly-eye-integrator, has only a slight divergence. A beam of this kind is generated, for example, by a laser light source and is broken up into a plurality of beams by the crossed cylinder lens plates. These beams are focused in the diaphragm plane of the illuminating system and there form a lattice of secondary light sources. The secondary light sources are only point shaped because of the slight divergence of the beam at the entrance of the fly-eye-integrator. The diaphragm plane is therefore only illuminated with discrete intensity peaks. For the fly-eye-integrators having refractive cylinder lenses, the number of the illuminated cylinder lenses is in the order of magnitude of 101. For this reason, only secondary light sources in the order of magnitude of 102 are disposed in the diaphragm plane. With the use of diffractive elements having a cylindrical effect, the number of secondary light sources can be increased because of the lesser element width; however, very high requirements are imposed on the quality of the diffractive element and especially on the peripheral sharpness by the very large imaging scale between the diffractive elements and the field to be illuminated.
The two pairs of cylinder lens plates in U.S. Pat. Nos. 4,682,885; 5,926,257 and 5,963,305 have different focal lengths and the cylinder lens plates of a pair, which are arranged downstream in respective light paths, are mounted in the vicinity of the diaphragm plane. For this reason, the cylinder lens plates of the two pairs, which are mounted upstream each in respective light directions, are arranged axially separated. If the fly-eye-integrator is illuminated with a beam of finite divergence such as generated by a mercury vapor lamp, then the axial separation of the upstream-mounted cylinder lens plates leads to an elliptical illumination of the diaphragm plane. The illumination of the image plane should be as rotationally symmetrical as possible for use in microlithography. For this reason, the use of additional diaphragms or filters is required whereby a light loss occurs.
U.S. Pat. No. 5,847,746 discloses an illuminating system which utilizes two crossed cylinder lens plates of different focal length for mixing light. The cylinder lens plates are illuminated with a parallel light beam of slight divergence. To avoid the situation that the diaphragm plane of a downstream projection objective is illuminated pointwise by intensity peaks, the focal lengths of the two cylinder lens plates are so adjusted that the secondary light sources are split into meridional and sagittal secondary light sources which are arranged so as to be defocused. In this way, the intensity peaks in the diaphragm plane are pulled apart to lines of lesser maximum intensity. Disadvantageous in this arrangement is the only partial illumination of the diaphragm plane and the fact that the point symmetry of the diaphragm illumination, which is usually desired, is deteriorated by the line-shaped intensity peaks.
U.S. Pat. No. 5,815,248 shows the use of a one-dimensional lattice in front of a fly-eye-integrator. The fly-eye-integrator does not comprise individual plates having cylinder lenses but a plate having rod-shaped lens elements which are arranged in a two-dimensional array. The lens elements must have an equally sized lateral aspect ratio for a field having a high lateral aspect ratio which is to be illuminated. Correspondingly, the secondary light sources, which are generated by the lens elements in the diaphragm plane, are non-uniformly distributed without the one-dimensional grid. With the aid of the one-dimensional grid, the array having lens elements is illuminated from three directions lying in a plane so that the number of secondary light sources, which are generated by the array, is increased. In this way, a more uniform distribution of the secondary light sources is obtained in the diaphragm plane which follows the fly-eye-integrator. The disadvantage of the use of a one-dimensional grid is the fact that the illumination of the diaphragm plane comprises discrete intensity peaks and no homogeneous illumination is achieved. In addition, the optical channels, which are generated by the lens elements, have a high lateral aspect ratio so that a large portion of the light channels is only partially illuminated in the conventional circular-shaped illumination of the fly-eye-integrator.
It is an object of the invention to provide an illuminating system for vacuum ultraviolet microlithography which operates in the vacuum ultraviolet range.
A first embodiment of the invention is an illuminating system for vacuum-ultraviolet (VUV) microlithography with a fly-eye-integrator as an optical integrator. A microlens array having rectangular-shaped individual lenses is mounted ahead of the fly-eye-integrator for increasing divergence. The fly-eye-integrator comprises two fly-eye-plates mounted in mutually opposite focal planes and these fly-eye-plates are formed from an array of individual lenses or from two crossed cylinder lens plates. The optical channels have a similar lateral aspect ratio as the field to be illuminated. The optical channels are formed by the individual lenses or the crossed cylindrical lenses. In order to be able to uniformly illuminate the diaphragm plane, the rectangular-shaped microlenses must have a similar lateral aspect ratio as the optical channels in order to increase divergence.
With this embodiment, it is disadvantageous that, for a field having a high lateral aspect ratio, the individual lenses likewise have to exhibit a high lateral aspect ratio. Such individual lenses are complex to produce. If one utilizes crossed cylindrical lens plates for the fly-eye plates, then the width of the cylinder lenses differs greatly for the two alignments when the crossed cylinder lenses have the same focal length. For cylinder lens plates of different alignment, various production methods must be applied under certain circumstances. In this configuration too, a large portion of the light channels is only incompletely illuminated with the conventional circular illumination of the fly-eye-integrator.
It is another object of the invention to provide an illuminating system having a fly-eye-integrator for a microlithographic projection exposure arrangement. It is a further object of the invention to provide such an illuminating system wherein the diaphragm plane can be illuminated symmetrically and as completely as possible at high efficiency.
The illuminating system of the invention is for a microlithographic projection exposure arrangement and includes: a light source; a first objective defining an optical axis; a fly-eye-integrator mounted on the axis and being illuminated by the first objective with light from the light source to form a plurality of beams; the fly-eye-integrator including a first one-dimensional array of first cylinder lenses having respective first cylinder axes; a second one-dimensional array of second cylinder lenses having respective second cylinder axes orientated perpendicularly to the first cylinder axes; a third one-dimensional array of third cylinder lenses having respective third cylinder axes orientated parallel to the first cylinder axes; and, a fourth one-dimensional array of fourth cylinder lenses having respective fourth cylinder axes orientated parallel to the second cylinder axes; the third one-dimensional array being configured for increasing divergence and being disposed upstream of the first one-dimensional array; and, the fourth one-dimensional array being configured for increasing divergence and being mounted on the optical axis upstream of the second one-dimensional array; a diaphragm plane on the optical axis directly downstream of the fly-eye-integrator; and, a condenser optic for superposing the plurality of beams into an image plane to illuminate a field.
In the illuminating system of the above embodiment, the rays, which emanate from a light source, are received by a first objective and form a beam in the exit plane of the first objective. This beam is preferably of parallel rays of low divergence. A fly-eye-integrator generates from this beam a plurality of beams which are superposed by a condenser optic in an image plane of the illuminating system and there preferably illuminate a rectangularly-shaped field. The longer field side is in the x-direction and the shorter side of the field is directed in the y-direction. The reticle for the microlithographic projection exposure arrangement or a masking arrangement, which is imaged by a downstream objective on the reticle, is imaged in the image plane of the illuminating system. The fly-eye-integrator includes at least a first plate and a second plate having rod-shaped cylinder lenses which are disposed in series perpendicular to the direction of the cylinder axes of the cylinder lenses. The cylinder lenses preferably have a cylindrical forward surface and a planar rearward surface. The cylindrical forward surface has a convex cross section perpendicular to the cylinder axis and a planar cross section parallel to the cylinder axis. The cylinder axes of the cylinder lenses of the two plates are preferably aligned perpendicular to each other. The cylinder axes of the cylinder lenses of the first plate are aligned in the x-direction. For this reason, the cylinder lenses of the first plate are identified in the following as y-field raster elements. The cylinder axes of the cylinder lenses of the second plate are aligned in the y-direction. For this reason, the cylinder lenses of the second plate are identified in the following as x-field raster elements. The y-field raster elements and the x-field raster elements generate a grid of secondary light sources in the diaphragm plane following the fly-eye-integrator. If the beam, which impinges on the fly-eye-integrator, exhibits a low divergence of the beam angles, then the expansion of the secondary light sources is low and the diaphragm plane is non-uniformly illuminated with discrete intensity peaks. In order to achieve a uniform illumination of the diaphragm plane, it is advantageous to mount a third plate forward of the plate having the y-field raster element viewed in the direction of the light with this third plate having rod-shaped cylinder lenses and to mount a fourth plate forward of the plate having x-field raster elements viewed in light direction with the fourth plate also having rod-shaped cylinder lenses. The cylinder lenses of the third plate are, in the direction of the cylinder axes, of the same length as the y-field raster elements but have a lesser width perpendicular to the direction of the cylinder axis than the y-field raster elements. These cylinder lenses are referred to in the following as y-microcylinder lenses. The cylinder axes of the y-microcylinder lenses are aligned parallel to the axes of the y-field raster elements. The cylinder lenses of the fourth plate are, in the direction of the cylinder axes, of the same length as the x-field raster elements but have, perpendicular to the direction of the cylinder axes, a lesser width than the x-field raster elements. The cylinder lenses are referred to in the following as x-microcylinder lenses. The cylinder axes of the x-microcylinder lenses are aligned parallel to the axes of the x-field raster elements. The microcylinder lenses, which are arranged forward of the field raster elements, lead to an increase of the divergence of the beam impinging on the field raster elements. In this way, the expansion of the secondary light sources is increased in the diaphragm plane and therefore the diaphragm plane is more uniformly illuminated. The advantage of the use of two plates mounted forward of the respective field raster elements and having microcylinder lenses is that the increase of divergence occurs in each case directly ahead of the field raster elements and only in one plane. The surface normal of these planes point in the direction of the cylinder axes of the microcylinder lenses and the corresponding field raster elements. The microcylinder lenses are configured to be refractive or diffractive.
It is advantageous when the x-field raster elements and the y-field raster elements have similar widths perpendicular to the respective cylinder axes. Preferably, the widths of the x-field raster elements and the y-field raster elements are the same size in the context of the manufacturing tolerances. In this way, the same manufacturing method can be applied for the x-field raster element and the y-field raster element. A further advantage of equal width x-field and y-field raster elements is that the secondary light sources in the diaphragm plane come to lie on a quadratic grid. In order to illuminate a rectangularly-shaped field for like widths for the x-field and y-field raster elements, the x-field and y-field raster elements have to have different focal lengths. Since the field raster elements are cylinder lenses, the input of a focal length for the field raster elements refers to the surface section in which the field raster elements exhibit an optical effect. The shorter field side in the image plane of the illuminating system points in the y-direction. For this reason, the focal length of the y-field raster element has to be greater than the focal length of the x-field raster element and preferably greater than 1.5 times and especially greater than by a factor of 2.
Preferably, the angle distribution of the rays, which impinge upon the field raster element, should be homogeneous at each position of the field raster element. This is not possible because the microcylinder lenses are discrete elements. In order to nonetheless illuminate the field raster element with an angle distribution as independent of position as possible it is advantageous when the width of the microcylinder lenses is less than the width of the corresponding field raster element. Advantageously, the width of the microcylinder lenses is less than half of the width of the corresponding field raster elements and is preferably less than {fraction (1/5 )} of the width of the corresponding field raster elements.
The secondary light sources generated by the field raster elements in the diaphragm plane are not homogeneously illuminated but exhibit intensity fluctuations because of the rastering of the microcylinder lenses. The number of intensity peaks within one secondary light source in one direction corresponds to the number of microcylinder lenses per field raster element. If the number of x-microcylinder lenses per x-field raster element is the same as the number of y-microcylinder lenses per y-field raster element, then the secondary light sources have equally as many intensity peaks in the x and y directions.
The expansion of the secondary light sources in the diaphragm plane is determined by the maximum angle with respect to the optical axis of the rays, which impinge upon the field raster elements, and by the spacing of the field raster elements from the diaphragm plane. This spacing corresponds approximately to the focal length of the field raster elements. The maximum angle is, in turn, fixed by the width and the focal length of the microcylinder lenses. The focal length of the microcylinder lenses refers to the area section wherein the microcylinder lenses have an optical effect. The maximum angle must be limited upwardly so that the individual secondary light sources do not overlap. These light sources are at a spacing in the diaphragm plane corresponding to the width of the field raster elements. Therefore, the ratio of width and focal length of the microcylinder lenses is preferably selected to be less than the ratio of width and focal length of the corresponding field raster elements.
On the other hand, the diaphragm plane should be illuminated as homogeneously as possible. For this reason, the maximum angle of the rays, which impinge upon the field raster element, should have a minimum value with respect to the optical axis. It is advantageous when the expansion of the secondary light sources corresponds at least to half the spacing of the secondary light sources. This is the case when the ratio of width and focal length of the microcylinder lenses amounts to at least half of the ratio of width and focal length of the corresponding field raster element.
Reflection losses occur at each boundary surface between materials of different refractive indexes. For this reason, the number of the boundary surfaces should be held as low as possible. Especially at wavelengths below 200 mm, it is an object to hold the number of optical elements as low as possible. It is therefore especially advantageous to join the plate with the y-microcylinder lenses and the plate with the corresponding y-field raster elements and/or the plate having the x-microcylinder lenses and the plate having the corresponding x-field raster elements each to a plate structured on the forward and rear surfaces. The joining can be achieved, for example, by wringing or via a cement area. Likewise, the simultaneous structuring of the forward and rearward surfaces of a plate is possible. In this way, two boundary surfaces are rendered unnecessary for each microcylinder lens field raster element plate built as one piece.
It is advantageous when the diaphragm plane is freely accessible in order to install diaphragm devices or control devices for measuring purposes in the diaphragm plane. The free working spacing should be at least 1.0 mm in the light direction upstream of the diaphragm plane. Preferably, this free work spacing should be at least 1.5 mm. The free work spacing downstream of the diaphragm plane should be at least 1 mm and preferably 3 mm.
The illumination of the diaphragm plane with diaphragm devices therein and therefore also the pupil illumination should be controllable. Conventional diaphragm devices have a circular opening for a so-called conventional pupil illumination or two openings for a so-called dipole pupil illumination with the openings being arranged point symmetrical to the diaphragm center or four openings for a so-called quadrupole pupil illumination with these four openings being arranged point symmetrically to the diaphragm center.
Individual field raster elements can be entirely or partially masked with additional diaphragm devices directly forward or rearward of the field raster elements. In this way, it is possible that only the regions of the field raster elements participate in the illumination of the diaphragm plane which regions are illuminated over their entire width. This leads to an increased uniformity of the illumination of the image plane of the illuminating system.
It is advantageous when the fly-eye-integrator has a plate having a two-dimensional arrangement of toric lenses in order to be able to image the x-field raster elements and the y-field raster elements with edge sharpness in the image plane of the illuminating system for expanded secondary light sources. Each toric lens together with a y-field raster element and an x-field raster element conjointly forms an optical channel. The optical channel includes not the total y-field raster element and x-field raster element but only the region of the field raster elements which results for an imaginary projection in the light direction as an intersection of the two y-field and x-field raster elements with the toric lens with these field raster elements being arranged so as to be crossed. In its center, the optical channel has a linear axis parallel to the optical axis of the fly-eye-integrator. The y-field raster element, x-field raster element and toric lens are arranged on this linear axis and the axis intersects the toric lens in the surface vertex. Corresponding to the widths of the field raster elements, the optical channels are delimited rectangularly and for the same field raster element width are limited quadratically. The two primary axes of the toric lenses are so aligned that the one primary axis runs parallel to the cylinder axes of the y-field raster elements and the other primary axis runs parallel to the cylinder axes of the x-field raster elements.
It is advantageous to so design the optical effects of the y-field raster element, x-field raster element and toric lenses that the back focal points of the optical channels lie in the proximity of the diaphragm plane. The optical channels are formed from a y-field raster element, an x-field raster element and a toric lens. In this way, a parallel beam, which impinges on the fly-eye-integrator, is first broken down into a plurality of beams and these beams are focused in the diaphragm plane or in the vicinity thereof whereby the secondary light sources are generated there.
The use of cylinder lenses or of toric lenses indicates the view in two mutually perpendicular planes. One plane has a surface normal pointing in the direction of the cylinder axes of the y-field raster elements of an optical channel and includes the axis of the viewed optical channel. This plane is referred to in the following as meridional plane. Optical quantities such as focal point and focal length for a viewed optical channel are given the attribute xe2x80x9cmeridionalxe2x80x9d when they are determined by rays which run exclusively in the meridional plane. A plane whose surface normal points in the direction of the cylinder axes of the x-field raster elements of an optical channel and which includes the axis of the viewed optical channel is referred to in the following as the xe2x80x9csagittal planexe2x80x9d. Optical quantities such as focal point and focal length for a viewed optical channel are given the attribute xe2x80x9csagittalxe2x80x9d when they are determined by rays which run exclusively in the sagittal plane.
In the determination of optical quantities for the optical channels, the microcylinder lenses are considered only with their center thickness as planar plates without their cylinder effect. The determination of the focal length or of the focal point of an optical channel therefore includes the y-microcylinder lenses and the x-microcylinder lenses considered as a planar plate. The influence of these equivalent planar plates on the focal lengths and focal points is, however, low.
It is advantageous to design the optical effects of the y-field raster elements and of the section of the toric lenses in the y-direction in such a manner that the meridional front focal points are located at the position of the y-field raster elements. The back focal point of the condenser optic, which follows the diaphragm plane, is located in the image plane of the illuminating system. For this reason, an optically conjugated arrangement of y-field raster elements and image plane results in the meridional section. The y-field raster elements are therefore imaged in the image plane. At the same time, it is advantageous if the optical effects of the x-field raster elements and of the section of the toric lenses, which points in the x-direction, are so designed that the sagittal front focal points are located at the position of the x-field raster elements. In this way, the x-field raster elements are likewise imaged in the image plane. The field in the image plane, which is to be illuminated, is delimited sharply at the edges by this measure. In addition, a very homogeneous illumination of the field is achieved by the superposition of the plurality of beams. The toric lenses contribute the largest portion of the optical effect for imaging of the field and are arranged in the proximity of the diaphragm plane. For this reason, the toric lenses are referred to in the following as pupil raster elements.
In lieu of the plate having a two-dimensional arrangement of toric lenses, the fly-eye-integrator can have a further plate having cylinder lenses whose cylindrical axes are aligned parallel to the cylinder axes of the x-field raster elements. This is especially the case for a microlithographic projection exposure arrangement designed as a scanner. These cylinder lenses are referred to in the following as x-pupil raster elements. The x-pupil raster elements preferably have a planar surface and a cylindrical surface. The cylindrical surface has a convex cross section perpendicular to the cylinder axis and a planar cross section parallel to the cylinder axis. The cylindrical surface is facing toward the diaphragm plane. Each x-pupil raster element together with a y-field raster element and an x-field raster element conjointly define an optical channel. The optical channel does not include the entire y-field raster element, x-field raster element and x-pupil raster element, but only the region of the field raster elements and of the x-pupil raster element which results with an imaginary projection in the light direction as an intersection of the y-field and the x-field raster elements arranged so as to be crossed with respect to each other and the x-pupil raster element. In its center, the optical channel has a linear axis running parallel to the optical axis of the fly-eye-integrator, with the y-field raster element, x-field raster element and x-pupil raster element being arranged on this linear axis. So that the secondary light sources can come to lie in the diaphragm plane or in the proximity thereof, it is advantageous when the back focal points of the optical channels are located there.
It is furthermore advantageous when the optical effect of the x-field raster elements and the x-pupil raster elements is so designed that the sagittal front focal points are located at the position of the x-field raster elements. The x-pupil raster elements and the condenser optic, which follows the diaphragm plane, then image the x-field raster elements in the image plane with high edge sharpness in the sagittal section.
To provide that the centroid rays of the beams run virtually parallel to the optical axis in the image plane of the illuminating system, it is advantageous to so configure the optical effect of the y-field raster elements that the spacing between the diaphragm plane and the back meridional focal points is approximately equal to half the meridional focal length.
Fly-eye-integrators which have only x-pupil raster elements in addition to the y-field raster elements and the x-field raster elements can be advantageously utilized in microlithographic projection exposure arrangements configured as a scanner. In these systems, only the short field end of the field, which is to be illuminated and which runs in the scan direction, has to be delimited with sharp edges. In the scan direction (that is, in the y-direction), a gradual increase of the intensity in pulsed light sources, such as laser light sources, is even advantageous in order to reduce pulse-quantization effects.
For an edge-like boundary of the illuminated field also in the y-direction, it is advantageous when the fly-eye-integrator has an additional plate with cylinder lenses in addition to the plate with the x-pupil raster elements. The cylindrical axes of the cylinder lenses are aligned parallel to the cylinder axes of the y-field raster elements. These cylinder lenses are characterized in the following as y-pupil raster elements. The y-pupil raster elements preferably have a planar and a cylindrical surface. The cylindrical surface includes a convex cross section perpendicular to the cylinder axis and a planar cross section parallel to the cylinder axis. The cylindrical surface is preferably facing toward the diaphragm plane.
Each y-pupil raster element together with an x-pupil raster element, an x-field raster element and a y-field raster element forms an optical channel. The optical channel does not include the entire y-pupil raster element, x-pupil raster element, x-field raster element and y-field raster element, but only the region of the field raster elements and the pupil raster elements which results for an imaginary projection in the light direction as an intersection of the selected field and pupil raster elements. In its center, the optical channel includes a linear axis running parallel to the optical axis of the fly-eye-integrator and the y-field raster element, x-field raster element, x-pupil raster element and y-pupil raster element are arranged on this linear axis. So that the secondary light sources come to lie in the diaphragm plane or in the proximity thereof, it is advantageous when the back focal points of the optical channels are located there.
To delimit the illuminated field with sharp edges in the image plane of the illuminating system, it is advantageous when the front meridional focal points of the optical channels are located at the location of the y-field raster elements and the front sagittal focal points of the optical channels are located at the location of the x-field raster elements.
In a similar manner as with the fly-eye-integrator having the pupil raster elements formed of toric lenses, it is advantageous when the y-field raster elements, the x-field raster elements, the x-pupil raster elements and the y-pupil raster elements all have the same widths. The optical channels are then quadratically limited and the secondary light sources lie in the reticle plane on a quadratic grid.
The pupil raster elements are arranged at a finite spacing to the diaphragm plane so that the diaphragm plane is accessible. This leads to unilluminated regions between the secondary light sources even when the pupil raster elements are illuminated to the edge of each optical channel with the aid of the x-microcylinder lenses and the y-microcylinder lenses. The unilluminated regions form unilluminated strips parallel to the cylinder axes of the x-field raster elements and the y-field raster elements. The unilluminated strips in the x-direction are arranged at a spacing of the width of the y-field raster elements and the unilluminated strips in the y-direction are arranged at a spacing of the width of the x-field raster elements. The widths of the unilluminated strips are less than 20% of the spacing of the adjacent unilluminated strips in order to illuminate the diaphragm plane as completely as possible.
It is further advantageous to select the widths of these unilluminated strips to be the same size independently of whether they are orientated in the direction of the cylinder axes of the y-field raster elements or of the x-field raster elements. In addition to an illumination of the diaphragm plane which is point symmetrical to the diaphragm center, one achieves in this way that two sectors can be illuminated with the same integral intensity with the two sectors being transposable into each other by mirroring on the x-axis and/or on the y-axis. In this way, each quadrant, which is delimited by the x-axis and y-axis, or each quadrant, which is delimited by two lines lying at an angle of 45xc2x0 to the x-axis and y-axis, has the same integral intensity. In this case, the diaphragm plane is illuminated mirror symmetrically to the x-axis and y-axis. Structures of the downstream reticle which are perpendicular to each other are imaged on the wafer with the same quality by the diaphragm plane illuminated in this way.
To reduce the reflection losses at boundary surfaces, it is advantageous to join the x-pupil raster elements and the y-pupil raster elements or to build these raster elements as a plate structured on both sides.
An illuminating system with a fly-eye-integrator described herein can be especially well used in a microlithographic projection exposure arrangement. The reticle is then mounted in the image plane or in a plane of the illuminating system conjugated to the image plane with the reticle having the structures which are to be imaged. In order to vary the size of the region to be illuminated on the reticle, it is advantageous when a masking device is arranged in the image plane of the illuminating system with this masking device being imaged on the reticle via an objective. A projection objective follows the reticle and this projection objective images the structures of the reticle on a light-sensitive object such as a wafer. Projection objectives of this kind are disclosed, for example, in U.S. Pat. No. 5,402,267 incorporated herein by reference.
Microstructured components having structures smaller than 500 nm (preferably less than 200 nm) can be produced with a microlithographic projection exposure arrangement configured in this manner.